Visceral sac and shell small in proportion to the rest of the body, which cannot be withdrawn into the shell; foot elongated, fin-shaped, with sucker, but without operculum.

The body is composed of a small and limited number of segments (not more than fourteen), and there is a sucker at each end of the body.

irXariis, broad; pianta thus meant a spreading shoot or sucker).

Moreover, the pollen, instead of consisting of separate cells or grains, consists of cells aggregated into "pollen-masses," the number varying in different genera, but very generally two, four, or eight, and in many of the genera provided at the base with a strap-shaped stalk or "caudicle" ending in a flattish gland or "viscid disk" like a boy's sucker.

d', Its sucker.